fix(DF-832): source GOV.UK Pay email from CYA confirmation field

src/server/plugins/engine/components/PaymentField.test.ts

@@ -952,26 +952,24 @@ describe('PaymentField', () => {
   })
 
   describe('dispatcher with email prepopulation', () => {
-    it('should pass valid email to createPayment', async () => {
-      const emailDef = {
-        title: 'Payment with email',
+    it('should pass state.userConfirmationEmailAddress to createPayment', async () => {
+      const def = {
+        title: 'Payment',
         name: 'myPayment',
         type: ComponentType.PaymentField,
         options: {
           amount: 50,
-          description: 'Test payment',
-          emailField: 'userEmail'
+          description: 'Test payment'
         }
       } satisfies PaymentFieldComponent
 
-      const mockYarSet = jest.fn()
       const mockRequest = {
         server: {
           plugins: {
             'forms-engine-plugin': { baseUrl: 'base-url' }
           }
         },
-        yar: { set: mockYarSet }
+        yar: { set: jest.fn() }
       } as unknown as FormRequestPayload
       const mockH = {
         redirect: jest
@@ -988,10 +986,10 @@ describe('PaymentField', () => {
           },
           getState: jest.fn().mockResolvedValueOnce({
             $$__referenceNumber: 'ref-123',
-            userEmail: 'test@example.com'
+            userConfirmationEmailAddress: 'cya@example.com'
           })
         },
-        component: emailDef,
+        component: def,
         sourceUrl: 'http://localhost:3009/test',
         isLive: false,
         isPreview: true
@@ -1008,26 +1006,87 @@ describe('PaymentField', () => {
 
       await PaymentField.dispatcher(mockRequest, mockH, args)
 
-      // Verify createPayment was called with the email as the 7th argument
       expect(postJson).toHaveBeenCalledWith(
         expect.any(String),
         expect.objectContaining({
           payload: expect.objectContaining({
-            email: 'test@example.com'
+            email: 'cya@example.com'
+          })
+        })
+      )
+    })
+
+    it('should not pass email when state.userConfirmationEmailAddress is missing', async () => {
+      const def = {
+        title: 'Payment',
+        name: 'myPayment',
+        type: ComponentType.PaymentField,
+        options: {
+          amount: 50,
+          description: 'Test payment'
+        }
+      } satisfies PaymentFieldComponent
+
+      const mockRequest = {
+        server: {
+          plugins: {
+            'forms-engine-plugin': { baseUrl: 'base-url' }
+          }
+        },
+        yar: { set: jest.fn() }
+      } as unknown as FormRequestPayload
+      const mockH = {
+        redirect: jest
+          .fn()
+          .mockReturnValueOnce({ code: jest.fn().mockReturnValueOnce('ok') })
+      } as unknown as FormResponseToolkit
+      const args = {
+        controller: {
+          model: {
+            formId: 'formid',
+            basePath: 'base-path',
+            services: mockServices,
+            conditions: {}
+          },
+          getState: jest.fn().mockResolvedValueOnce({
+            $$__referenceNumber: 'ref-123'
+          })
+        },
+        component: def,
+        sourceUrl: 'http://localhost:3009/test',
+        isLive: false,
+        isPreview: true
+      } as unknown as PaymentExternalArgs
+
+      // @ts-expect-error - partial mock
+      jest.mocked(postJson).mockResolvedValueOnce({
+        payload: {
+          state: { status: 'created' },
+          payment_id: 'pay-id',
+          _links: { next_url: { href: '/next' } }
+        }
+      })
+
+      await PaymentField.dispatcher(mockRequest, mockH, args)
+
+      expect(postJson).toHaveBeenCalledWith(
+        expect.any(String),
+        expect.objectContaining({
+          payload: expect.not.objectContaining({
+            email: expect.anything()
           })
         })
       )
     })
 
-    it('should not pass email when emailField value is empty', async () => {
-      const emailDef = {
-        title: 'Payment with empty email',
+    it('should not pass email when state.userConfirmationEmailAddress is not a string', async () => {
+      const def = {
+        title: 'Payment',
         name: 'myPayment',
         type: ComponentType.PaymentField,
         options: {
           amount: 50,
-          description: 'Test payment',
-          emailField: 'userEmail'
+          description: 'Test payment'
         }
       } satisfies PaymentFieldComponent
 
@@ -1054,10 +1113,10 @@ describe('PaymentField', () => {
           },
           getState: jest.fn().mockResolvedValueOnce({
             $$__referenceNumber: 'ref-123',
-            userEmail: ''
+            userConfirmationEmailAddress: { not: 'a string' }
           })
         },
-        component: emailDef,
+        component: def,
         sourceUrl: 'http://localhost:3009/test',
         isLive: false,
         isPreview: true
@@ -1074,7 +1133,6 @@ describe('PaymentField', () => {
 
       await PaymentField.dispatcher(mockRequest, mockH, args)
 
-      // Verify createPayment was called WITHOUT an email field
       expect(postJson).toHaveBeenCalledWith(
         expect.any(String),
         expect.objectContaining({

src/server/plugins/engine/components/PaymentField.ts

@@ -270,15 +270,10 @@ export class PaymentField extends FormComponent {
     const payCallbackUrl = `${baseUrl}/payment-callback?uuid=${uuid}`
     const paymentPageUrl = args.sourceUrl
 
-    // Prepopulate GOV.UK Pay email if emailField is configured.
-    // The referenced EmailAddressField validates with joi.string().email()
-    // at input time, so the value in state is already validated.
     let prefilledEmail: string | undefined
-    if (options.emailField) {
-      const emailValue = state[options.emailField]
-      if (typeof emailValue === 'string' && emailValue) {
-        prefilledEmail = emailValue
-      }
+    const userConfirmationEmail = state.userConfirmationEmailAddress
+    if (typeof userConfirmationEmail === 'string' && userConfirmationEmail) {
+      prefilledEmail = userConfirmationEmail
     }
 
     const amountInPence = Math.round(resolvedAmount * 100)